LTV1 is an essential ribosome biogenesis factor required for small (40S) ribosomal subunit assembly and maturation 1. Primary function: LTV1 facilitates incorporation of ribosomal proteins (Rps3, Rps10, and RACK1) into the 40S subunit head and promotes nascent subunit export from the nucleus to the cytoplasm 2. Mechanism: LTV1 functions as a chaperone during early and late-stage 40S assembly, with its release from pre-40S particles controlled by casein kinase 1δ/ε phosphorylation, a critical step for ribosome maturation and translational quality control 34. Disease relevance: Biallelic LTV1 mutations cause LIPHAK syndrome (LTV1-associated Inflammatory Poikiloderma with Hair abnormalities and Acral Keratoses), a ribosomopathy characterized by dermatological abnormalities 1. In zebrafish models, ltv1 deficiency impairs digestive organ and hematopoietic development through p53-independent mechanisms 5. Clinical significance: LTV1 dysfunction affects translational fidelity and ribosome-mediated quality control; cancer cells exploit reduced LTV1 levels to generate heterogeneous ribosome populations promoting stress survival 2. CK1δ inhibitors used therapeutically disrupt LTV1-mediated ribosome assembly, representing a validated anticancer mechanism 3.